#ifndef _ASM_GENERIC_GPIO_H
#define _ASM_GENERIC_GPIO_H
+#include <linux/types.h>
+#include <linux/errno.h>
+
+#ifdef CONFIG_GPIOLIB
+
+#include <linux/compiler.h>
+
+/* Platforms may implement their GPIO interface with library code,
+ * at a small performance cost for non-inlined operations and some
+ * extra memory (for code and for per-GPIO table entries).
+ *
+ * While the GPIO programming interface defines valid GPIO numbers
+ * to be in the range 0..MAX_INT, this library restricts them to the
+ * smaller range 0..ARCH_NR_GPIOS-1.
+ */
+
+#ifndef ARCH_NR_GPIOS
+#define ARCH_NR_GPIOS 256
+#endif
+
+static inline int gpio_is_valid(int number)
+{
+ /* only some non-negative numbers are valid */
+ return ((unsigned)number) < ARCH_NR_GPIOS;
+}
+
+struct seq_file;
+struct module;
+
+/**
+ * struct gpio_chip - abstract a GPIO controller
+ * @label: for diagnostics
+ * @dev: optional device providing the GPIOs
+ * @owner: helps prevent removal of modules exporting active GPIOs
+ * @request: optional hook for chip-specific activation, such as
+ * enabling module power and clock; may sleep
+ * @free: optional hook for chip-specific deactivation, such as
+ * disabling module power and clock; may sleep
+ * @direction_input: configures signal "offset" as input, or returns error
+ * @get: returns value for signal "offset"; for output signals this
+ * returns either the value actually sensed, or zero
+ * @direction_output: configures signal "offset" as output, or returns error
+ * @set: assigns output value for signal "offset"
+ * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
+ * implementation may not sleep
+ * @dbg_show: optional routine to show contents in debugfs; default code
+ * will be used when this is omitted, but custom code can show extra
+ * state (such as pullup/pulldown configuration).
+ * @base: identifies the first GPIO number handled by this chip; or, if
+ * negative during registration, requests dynamic ID allocation.
+ * @ngpio: the number of GPIOs handled by this controller; the last GPIO
+ * handled is (base + ngpio - 1).
+ * @can_sleep: flag must be set iff get()/set() methods sleep, as they
+ * must while accessing GPIO expander chips over I2C or SPI
+ *
+ * A gpio_chip can help platforms abstract various sources of GPIOs so
+ * they can all be accessed through a common programing interface.
+ * Example sources would be SOC controllers, FPGAs, multifunction
+ * chips, dedicated GPIO expanders, and so on.
+ *
+ * Each chip controls a number of signals, identified in method calls
+ * by "offset" values in the range 0..(@ngpio - 1). When those signals
+ * are referenced through calls like gpio_get_value(gpio), the offset
+ * is calculated by subtracting @base from the gpio number.
+ */
+struct gpio_chip {
+ const char *label;
+ struct device *dev;
+ struct module *owner;
+
+ int (*request)(struct gpio_chip *chip,
+ unsigned offset);
+ void (*free)(struct gpio_chip *chip,
+ unsigned offset);
+
+ int (*direction_input)(struct gpio_chip *chip,
+ unsigned offset);
+ int (*get)(struct gpio_chip *chip,
+ unsigned offset);
+ int (*direction_output)(struct gpio_chip *chip,
+ unsigned offset, int value);
+ void (*set)(struct gpio_chip *chip,
+ unsigned offset, int value);
+
+ int (*to_irq)(struct gpio_chip *chip,
+ unsigned offset);
+
+ void (*dbg_show)(struct seq_file *s,
+ struct gpio_chip *chip);
+ int base;
+ u16 ngpio;
+ unsigned can_sleep:1;
+ unsigned exported:1;
+};
+
+extern const char *gpiochip_is_requested(struct gpio_chip *chip,
+ unsigned offset);
+extern int __must_check gpiochip_reserve(int start, int ngpio);
+
+/* add/remove chips */
+extern int gpiochip_add(struct gpio_chip *chip);
+extern int __must_check gpiochip_remove(struct gpio_chip *chip);
+
+
+/* Always use the library code for GPIO management calls,
+ * or when sleeping may be involved.
+ */
+extern int gpio_request(unsigned gpio, const char *label);
+extern void gpio_free(unsigned gpio);
+
+extern int gpio_direction_input(unsigned gpio);
+extern int gpio_direction_output(unsigned gpio, int value);
+
+extern int gpio_get_value_cansleep(unsigned gpio);
+extern void gpio_set_value_cansleep(unsigned gpio, int value);
+
+
+/* A platform's <asm/gpio.h> code may want to inline the I/O calls when
+ * the GPIO is constant and refers to some always-present controller,
+ * giving direct access to chip registers and tight bitbanging loops.
+ */
+extern int __gpio_get_value(unsigned gpio);
+extern void __gpio_set_value(unsigned gpio, int value);
+
+extern int __gpio_cansleep(unsigned gpio);
+
+extern int __gpio_to_irq(unsigned gpio);
+
+#ifdef CONFIG_GPIO_SYSFS
+
+/*
+ * A sysfs interface can be exported by individual drivers if they want,
+ * but more typically is configured entirely from userspace.
+ */
+extern int gpio_export(unsigned gpio, bool direction_may_change);
+extern void gpio_unexport(unsigned gpio);
+
+#endif /* CONFIG_GPIO_SYSFS */
+
+#else /* !CONFIG_HAVE_GPIO_LIB */
+
+static inline int gpio_is_valid(int number)
+{
+ /* only non-negative numbers are valid */
+ return number >= 0;
+}
+
/* platforms that don't directly support access to GPIOs through I2C, SPI,
* or other blocking infrastructure can use these wrappers.
*/
gpio_set_value(gpio, value);
}
+#endif /* !CONFIG_HAVE_GPIO_LIB */
+
+#ifndef CONFIG_GPIO_SYSFS
+
+/* sysfs support is only available with gpiolib, where it's optional */
+
+static inline int gpio_export(unsigned gpio, bool direction_may_change)
+{
+ return -ENOSYS;
+}
+
+static inline void gpio_unexport(unsigned gpio)
+{
+}
+#endif /* CONFIG_GPIO_SYSFS */
+
#endif /* _ASM_GENERIC_GPIO_H */
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